It is used to measure the potential difference between two points

The ammeter is an instrument used to measure the intensity of the flow of electric current that passes through the cross section of a conductor.

They are used to control two-speed motors that are normally used in industrial equipment, where changing speed is necessary.

System used in motors with two voltages with a relationship (Y-∆) and at least six terminals, with the lowest voltage coinciding with the mains voltage.

Reverse switch, whose characteristic is that it is not locked in the "on" position, that is, when you release the handle, it returns to the zero position (key off).

They are used to reverse the direction of rotation of three-phase electric motors.